#include <iostream>
#include <bits/stdc++.h>

using namespace std;

ifstream in("darb.in");
ofstream out("darb.out");

#define sizee 100005

vector<int> la[sizee];
int n;
int parent[sizee];

int bfs1()
{
    queue<int> q;
    q.push(1);
    parent[1] = -1;

    while(q.size())
    {
        for (auto to: la[q.front()])
        {
            if (parent[to] == 0)
            {
                q.push(to);
                parent[to] = q.front();
            }
        }
        if (q.size() == 1)
            return q.front();
        q.pop();
    }
}

int bfs2(int from)
{
    for (int i = 1; i <= n; i++)
        parent[i] = 0;
    queue<int> q;
    q.push(from);
    while (q.size())
    {
        for (auto to: la[q.front()])
        {
            if (parent[to] == 0)
            {
                q.push(to);
                parent[to] = parent[q.front()] + 1;
            }
        }
        if (q.size() == 1)
            return parent[q.front()] + 1;
        q.pop();
    }
}

int main()
{
    in >> n;
    for (int i = 1; i <= n-1; i++)
    {
        int x,y;
        in >> x >> y;
        la[x].push_back(y);
        la[y].push_back(x);
    }

    int far = bfs1();

    int max_dist = bfs2(far);
    out << max_dist;

    return 0;
}